Efficient coupling between core and fluidic channel in a solid-core photonic crystal fiber

An index-guiding photonic crystal fiber with one hole adjacent to the solid core filled with liquid is theoretically and experimentally investigated. The use of an index-matched liquid induces efficient and short-range coupling from the solid core to the fluidic channel and back, which can be used to optically probe and/or pump the inserted liquid. Experimentally, the use of a micropipette allowed for selective filling the desired air hole. By varying the filled fiber length, the periodicity of the observed spectral modulation could be tuned. One fiber sample was then filled with a CdSe quantum dot colloid; pumping via the solid core resulted in photoluminescence that partially exited the fiber via the solid core, showing the filled waveguide's potential to offer distributed quantum dot pumping and an efficient collection method for the generated spontaneous emission.